Interannual variability of biomass burning aerosol optical depth in southern Amazonia, and the effec

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Inter-annual variability of biomass burning
aerosol optical depth in southern Amazonia, and
the effects of these aerosols on the diurnal
cycle of solar flux reduction

• T.F. Eck1, B.N. Holben1, J.S. Schafer1, P.
  Artaxo2, M.A. Yamasoe3, A.S. Procopio2, E.M.
  Prins4, J.M. Feltz5, O. Dubovik1, and A. Smirnov1
• 1NASA/GSFC,Code 923, Greenbelt, MD, USA
• 2Instituto de Fisica, Universidade de São Paulo,
  São Paulo-SP, Brazil
• 3Instituto de Astronomia, Universidade de São
  Paulo, São Paulo-SP, Brazil
• 4NOAA/NESDIS/ORA, Madison, WI
• 5UW-Madison, CIMSS, Madison, WI

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Comparison of Optical Characteristics of Biomass
Burning Aerosols Monitored at AERONET Sites in
Worldwide Locations Inter-annual Variability of
Aerosol Optical Depth (AOD) in Rondônia and Mato
Grosso and the Relationship to GOES Satellite
Fire Count Variability The Effects of High AOD on
the Diurnal Cycle of Flux Reduction in Rondônia
during the Peak of the Burning Season for the
UVA, PAR, and Total SW Fluxes
Primary Forest Burn - Jamari, Rondonia, Sepember
1995
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Dubovik et al. 2002
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400-700 nm Effective Values AOD1.16
SSA0.90
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300-4000 nm Effective Values AOD0.77
SSA0.89
320-400 nm Effective Values AOD2.03
SSA0.91
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Temporal Delay in Mid-Morning (Clear Day)
Equivalent Flux Level September 15 12 Hour Day
Length (Sunrise-Sunset)
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• Summary and Conclusions
• Comparison of smoke size distributions and single
  scattering albedo of smoke from different
  regions/environments shows Amazonian forest
  region smoke hazes have lower absorption (higher
  SSA) and larger particles than smoke from
  savanna/cerrado burning
• Seasonal variation in single scattering albedo
  was observed at Cuiaba (cerrado region) possibly
  as a result of seasonal differences in the
  regions burned, transport of smoke from these
  various source regions, and greater cloud
  processing of smoke later in the burning season.
  No seasonal variation in SSA was noted for the
  Amazonian forest sites.
• Inter-annual variation in both smoke AOD and
  satellite fire counts have shown very large
  variability over the last decade as a result of
  meteorological conditions (rainfall extent and
  timing, atmospheric stability, etc.) and possibly
  recent regulations on burning
• Direct effect aerosol attenuation of solar fluxes
  at the surface from the high smoke loading in
  Southern Amazonia result in significant delays
  diurnally in fluxes at the surface. Timing
  differences in equivalent flux levels may
  influence convective cloud growth, alter the
  photoperiod for plants, and reduce the time
  interval for high UV fluxes which may have
  implications for survival of bacteria, insect
  activity, and plant responses.

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